(GT - Draft Report 005) Paeldon - Amvel Business Park, San Dionisio, Paranaque City 2017.04.26 PDF

 

 

GEOTECHNICAL INVESTIGATION REPORT

Subsu rface Investigatio Investigation n for th e

 AL K HEMY OFFIC  ALK OFFICE E WAREHOUSE Lott 2, PCS Lo PCS-0 -000-01 0152 5243 43,, Amvel Am vel Busi Bu siness ness Pa Park rk,, Brgy. Brg y. S San an Dioni Dionisio sio,, Para Parañaque ñaque City

 APRIL 2017

 

Subsurface Investigation for the Alkhemy Office Warehouse Lot 2, PCS-00-015243, Amvel Business Park, Brgy. San Dionisio, Parañaque City

GEOTECHNICAL INVESTIGATION REPORT Subsurface Investigation Investigation f or the  ALKHEMY  AL KHEMY OFFI OFFICE CE WAREHOUSE Lot 2, P PCS CS-0 -000-01 0152 5243 43,, Am Amvel vel Bu sin ess Pa Park, rk, B rgy. rg y. Sa San n Dio Dionis nis io, Parañaque Pa rañaque City

Table Ta ble of Contents

Contents

Page

1.0 

INTRODUCTION

1 

2.0 

PROJECT LOCATION AND REGIONAL REGIONAL GEOLOGY

1 

3.0 

FIELD INVESTIGATIONS

2 

4.0 

LAB ORATORY TESTING TESTING

4 

5.0 

RESULTS OF SUBSURFACE INVESTIGATION

5 

6.0 

EVALUATION EVAL UATION AND RECOMMENDATIONS

6 

7.0 

OTHER COMMENTS

 Appen  Ap pendi di ces Borehole Locations Plan Plan Idealized Soil Profiles Final Borehole Logs and Summary of Test Test Results Photographs

13 

 

Subsurface Investigation for the Alkhemy Office Warehouse Lot 2, PCS-00-015243, Amvel Business Park, Brgy. San Dionisio, Parañaque City

1.0

INTRODUCTION This report presents the geotechnical evaluation of the results of subsurface investigation conducted at the site of the PROPOSED ALKHEMY OFFICE WAREHOUSE,,  located at Lot 2, pcss-00-015243, Amvel Business Park, Brgy. WAREHOUSE San Dionisio, Parañaque City. The geotechnical investigation consisted of drilling three (3) boreholes within the site in order to assess the subsoil conditions and evaluate its characteristics. The soil samples recovered were then brought to the soil laboratory for analysis and testing. Laboratory tests on selected soil samples include:        

•

• •

•

Soil Classification using the USCS (ASTM D2487) Grain Size Analysis (ASTM D422) Atterberg Limits (ASTM D4318) Determination of Moisture Content (ASTM D2216)

This report presents the field and laboratory procedures adopted in the investigation as well as the evaluation of the test results for foundation analysis and design. Subsurface conditions are presented in the form of idealized soil profile and borehole log that also include the results of the field and laboratory tests on soil samples. Soil-Philippines Index Testin Testin g, Inc.  Inc.  undertook the geotechnical investigation at the site from March 24 to 30, 2017. The geotechnical investigation followed the procedures recommended by the  American Society Society of Testing and M Materials aterials (ASTM).

2.0

PROJECT LOCA LOCATION TION AND REGIO REGIONAL NAL GEOLOGY The project involves the construction of the Alkhemy Office Warehouse located at Lot 2, PCs-00-015243, Amvel Business Park, Brgy. Brgy. San Dionisio, Parañaque City. The geology of the project site is characterized by quaternary alluvial deposits of variable thickness, consisting of clays, silts and sands. These deposits are underlain by the Guadalupe Tuff Formation (GTF). GTF, which underlie most of Metro Manila and nearby areas is a horizontally bedded rock commonly referred to as “adobe”. It consists of well laid rock formation of tuffaceous sandstone, tuffaceous siltstone and shale being the weakest member.

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Subsurface Investigation for the Alkhemy Office Warehouse Lot 2, PCS-00-015243, Amvel Business Park, Brgy. San Dionisio, Parañaque City

Project Site 

Figure 1. Satellite Image of the Project Site (Google Earth)

Guadalupe Formation

 

Quaternary  All uv ium iu m

Project Area

 

Figure 2: Extract fr om the Geologic Map of Manila and Quezon Quezon City Quadrangle (Source: MGB)

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Subsurface Investigation for the Alkhemy Office Warehouse Lot 2, PCS-00-015243, Amvel Business Park, Brgy. San Dionisio, Parañaque City

3.0

FIELD INVEST INVESTIGATIONS IGATIONS The field investigation within the site consisted of drilling three (3) boreholes. The final depth, water level reading, and date of drilling are presented in Table 1. Table 1: Summary of Field Investigation

Borehole Number

Final Depth

Water Level

Date Da te of Drilli ng

BH-01

15.00 m

1.00 m

24 24 –  25 March 2017  – 25

BH-02

15.00 m

1.00 m

28 28 –  29 March 2017  – 29

BH-03

15.00 m

1.00 m

27 27 –  30 March 2017  – 30

Figure 3. Borehole Locati on Plan (Source: SPI) SPI) 

Washboring procedures were employed in order to advance the drill hole and the Standard Penetration Test was done in order to get the penetration resistance profile of the underlying soils. The Standard Penetration Test (SPT) was done in accordance with ASTM specifications. For each test, a 2-inch (50.8mm) outside diameter Spoon Sampler is driven into the soil a distance of 18 (460mm) inches by means of a 140 lb. (63.5 kg.) driving mass falling free from a height of 30 inches (760mm). (760mm). The number of blows needed to drive the sampler 18 inches (460mm) is recorded and the number of blows needed to drive the last 12 inches (305mm) is taken as the N-value. Soil samples were recovered using the spoon sampler and were then taken to the laboratory for analysis and testing. Complementing the field activities is the laboratory testing of the samples obtained. The results of the field works and laboratory investigation were then

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Subsurface Investigation for the Alkhemy Office Warehouse Lot 2, PCS-00-015243, Amvel Business Park, Brgy. San Dionisio, Parañaque City

used to establish the parameters for determining the type of foundation, level of foundation and bearing capacities.

4.0

LA LABORA BORATORY TORY TESTIN TESTING G Representative soil samples obtained during drilling were subjected to the following laboratory tests: Grain Size Analys is per ASTM D4 D422 22 This method covers the quantitative determination of the distribution of particle sizes of soils. Soil was passed through a series of sieves, the weight of soil retained in each sieve determined and recorded. For each sample analyzed, a gradation curve was drawn based on the percent finer weight. Determination of Moisture Content per ASTM D2216 This method covers the laboratory determination of the water (moisture) content of soil by weight. The moisture content of a material is defined as the ratio, expressed as a percentage, of the mass of pore water in a given mass of material to the mass of the solid material particles.  Atter  At ter ber g L im it Test per ASTM D4318 This test method covers the determination of the liquid limit, plastic limit, and the plasticity index of soils. Liquid Limit of Soils The liquid limit of a soil is the water content expressed as a percentage of the weight of the oven-dried soil after attaining the condition betwee between n the liquid and plastic states. Plastic Limit and Plasticity Index of Soils The plastic limit of a soil is the water content, expressed as a percenta percentage ge of the mass of the oven-dried soil after attaining the condition between the plastic and semi-solid states. Plasticity Index is defined as the difference between the liquid and plastic limits of the soil. Soil Class ifi catio n Tests per ASTM D248 D2487 7 This standard describes a system for classifying mineral and organo-mineral soils for engineering purposes based on laboratory determination of particle size characteristics, liquid limit and plasticity index.

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Subsurface Investigation for the Alkhemy Office Warehouse Lot 2, PCS-00-015243, Amvel Business Park, Brgy. San Dionisio, Parañaque City

5.0

RESULTS OF SUBSURF SUBSURFACE ACE INVESTIGATION The results of the subsurface investigation show that the site subsoil predominantly consists of sand, silt, and clay of varying relative condition and consistency. Within 1.0 meter to 9.0 meters depth, SPT N-values are generally indicative of loose to medium dense relative condition. Beneath these layers, medium dense to dense sand and medium stiff to very stiff silt and clay were encountered. Tuff layers were not encountered in the investigation. Water levels were recorded at a 1.0 meter depth below ground surface during the conduct of the field tests. Table 2 to Table 4 present the idealized subsurface condition based on the results of field and laboratory testing. Table 2: Idealized Idealized Subsurface Condi tion at BH-0 BH-01 1

Depth, m

Soil Classification (USCS)

SPT Nvalue

Remarks (Consistency / Relative Condition)

0.0 – 0.0  –  1.0

CL

12

Stiff

1.0 – 1.0  –  9.0

SC / SM

5 –  –  19

Loose – Loose  – Medium  Medium Dense

9.0 – 9.0  –  13.5

ML / SC / SM

15 – 15 –  23

Medium Dense

13.5 – 13.5  –  15.0

CL

27

Very Stiff

Depth, m

Soil Classification (USCS)

SPT Nvalue

Remarks (Consistency / Relative Condition)

0.0 – 0.0  –  1.0

CL

16

Stiff

1.0 – 1.0  –  5.0

SC / SM / SP

5 –  –  10

Loose

5.0 – 5.0  –  9.0

SC / SM

30 – 30 –  47

Dense

9.0 – 9.0  –  15.0

MH / CL

8 –  –  16

Medium Stiff – Stiff  – Stiff  Stiff

Table 3: Idealized Idealized Subsurface Condi tion at BH-0 BH-02 2

Table 4: Idealized Idealized Subsurface Condi tion at BH-0 BH-03 3

Depth, m

Soil Classification (USCS)

SPT Nvalue

Remarks (Consistency / Relative Condition)

0.0 – 0.0  –  2.0

SC

25 – 25 –  33

Medium Dense - Dense

2.0 – 2.0  –  6.0

SM / CH

4 –  –  6

Loose / Soft

6.0 – 6.0  –  9.0

SM

44 – 44 –  52

Dense – Dense  – Very  Very Dense

9.0 – 9.0  –  15.0

SC / SM / MH / CL

6 –  – 14  14

Medium Stiff – Stiff – Stiff  Stiff / Loose

Based on these results, geotechnical evaluation was carried out to obtain the geotechnical parameters necessary for the analysis and design of foundation and substructures.

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Subsurface Investigation for the Alkhemy Office Warehouse Lot 2, PCS-00-015243, Amvel Business Park, Brgy. San Dionisio, Parañaque City

6.0

EVALU EVALUATION ATION AND RECOM RECOMMENDATIONS MENDATIONS Liquefaction Potential Soil liquefaction is a phenomenon that occurs mostly in saturated medium to fine-grained sands. During liquefaction, a mass of soil loses a large percentage of its shear resistance when subjected to monotonic, cyclic or shock loading, and flows in a manner resembling a liquid. Much of the damage on substructures and foundation during earthquake is attributed to this phenomenon.  A reliable method for initially assessing liquefaction potential based on SPT data was developed by Seed and Idriss in a series of their publications. Based from their study, the following criteria describe soils with liquefaction potential: potential: • •

• •

•

  SPT N-value < 10;   D50  (soil particle diameter at 50% passing) is between 0.02mm to 2.0mm;   Saturated Saturat ed soil material or below the water table;   Non-plastic fines (cohesionless); (cohesionless); and   Proximity to a source capable of generating ground shaking.

The results of the field and laboratory tests reveal that upper layers of the subsoil are generally composed of very loose to medium dense sand and silt.  As such, the project site is evidently prone to liquefaction. liquefaction. This is consistent with the liquefaction hazard map of Metro Manila (Figure 4), 4), as published by PHIVOLCS. Liquefaction potential is established by the Factor of Safety (FSL). It is calculated as the ratio of the Cyclic Resistance Ratio (CRR) to the Cyclic Stress Ratio (CSR). This is based on the most recent methods recommended by the National Center for Earthquake Engineering Research (NCEER) Workshop on Liquefaction and Special Publication 117 (Guidelines in Analyzing and Mitigating Liquefaction in California). The results of the analysis indicate that liquefaction-induced settlement ranges from 7.15 to 12.89 cm as presented in Figure in Figure 5 to Figure 7. Table 5: Summary of Thicknesses / Depths of Potentially Liquefiable Layer

Borehole

Depth o f Potentially Depth Liquefiable Layer, m

 Av erage erag e Com put pu t ed Settl Se ttl ements, ements, cm

BH-01

1.0 – 1.0  –  7.0

7.15

BH-02

1.0 – 1.0  –  5.0

9.59

BH-03

2.0 – 2.0  – 3.0,  3.0, 4.0 – 4.0  – 6.0,  6.0, 10.5 – 12.0, 10.5 –  12.0, 13.5 – 13.5  – 15.0  15.0

12.89

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Subsurface Investigation for the Alkhemy Office Warehouse Lot 2, PCS-00-015243, Amvel Business Park, Brgy. San Dionisio, Parañaque City

 

Project Site

Figure 4. Liquefacti on Hazard Map of Metro Manila (Source: PHIVO PHIVOLCS) LCS)

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Subsurface Investigation for the Alkhemy Office Warehouse Lot 2, PCS-00-015243, Amvel Business Park, Brgy. San Dionisio, Parañaque City

LIQUEFACTION ANALYSIS  AL KHEMY OFFICE OFFICE WA REH REHOU OUSE SE Ho l e No .=BH-01 W Wa at er D ept h =0 m Soil Des c ription (m (m))0

M agn it u de=7.2  A  Acceler cceleratio atio n=0.4g

Raw Unit Fines Shear Stress Ratio SPT 12 Weight 17 N% oLq 0

1

17 18

39

2

5

17

46

3

8

17

27

4

12 18

24

5

9

17

26

6

18 18

18

19 18

17

23 18

54

22 18

42

15 18

32

27 19

NoLq

1

Fac tor of Saf ety

Settlement

0 1

0 ( c m)

5

10

7

8

9 10

11

12

13   m   o   c  .    h   c   e    t    l    i   v    i   c  .   w   w   w    A    S    U   e   r   a   w    t    f   o    S    h   c   e    T    l    i   v    i    C   o   r    P   y    f   e   u   q    i    L

14

fs1=1 15

CRR CSR f s1 Shaded Zone has Liquefaction Potential

S = 7.15 cm Saturated Unsaturat.

16

17

18

19

20

C i vi l Tech C or por at i on

San Dionisio, Parañaque City

Plate A-1

Figure 5. Liquefaction Analysis for BH-01 

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Subsurface Investigation for the Alkhemy Office Warehouse Lot 2, PCS-00-015243, Amvel Business Park, Brgy. San Dionisio, Parañaque City

LIQUEFACTION ANALYSIS  AL KHEMY OFFICE OFFICE WA REH REHOU OUSE SE Ho l e No .=BH-02 W Wa at er D ept h =0 m Soil Des c ription (m (m))0

M agn it u de=7.2  A  Acceler cceleratio atio n=0.4g

Raw Unit Fines Shear Stress Ratio SPT 16 Weight 18 N% oLq 0

1

10 18

38

2

7

17

9

3

5

17

17

4

5

17

34

5

30 18

35

6

34 19

48

47 19

28

8

17

NoLq

10 17

NoLq

12 18

NoLq

16 18

NoLq

1

Fac tor of Saf ety

Settlement

0 1

0 ( c m)

5

10

7

8

9 10

11

12

13   m   o   c  .    h   c   e    t    l    i   v    i   c  .   w   w   w    A    S    U   e   r   a   w    t    f   o    S    h   c   e    T    l    i   v    i    C   o   r    P   y    f   e   u   q    i    L

14

fs1=1 15

CRR CSR f s1 Shaded Zone has Liquefaction Potential

S = 9.59 cm Saturated Unsaturat.

16

17

18

19

20

C i vi l Tech C or por at i on

San Dionisio, Parañaque City

Plate A-1

Figure 6. Liquefaction Analysis for BH-02

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Subsurface Investigation for the Alkhemy Office Warehouse Lot 2, PCS-00-015243, Amvel Business Park, Brgy. San Dionisio, Parañaque City

LIQUEFACTION ANALYSIS  AL KHEMY OFFICE OFFICE WA REH REHOU OUSE SE Ho l e No .=BH-03 W Wa at er D ept h =0 m Soil Des c ription (m (m))0

M agn it u de=7.2  A  Acceler cceleratio atio n=0.4g

Raw Unit Fines Shear Stress Ratio SPT 33 Weight 19 4% 6

1

25 18

25

2

6

17

16

3

4

15

NoLq

4

5

17

15

5

6

17

25

6

44 19

47

52 20

39

14 18

66

9

17

39

6

16

NoLq

0

1

Fac tor of Saf ety

Settlement

0 1

0 ( c m)

5

50

7

8

9 10

11

12

13   m   o   c  .    h   c   e    t    l    i   v    i   c  .   w   w   w    A    S    U   e   r   a   w    t    f   o    S    h   c   e    T    l    i   v    i    C   o   r    P   y    f   e   u   q    i    L

14 18

45

14

fs1=1 15

CRR CSR f s1 Shaded Zone has Liquefaction Potential

S = 12.89 cm Saturated Unsaturat.

16

17

18

19

20

C i vi l Tech C or por at i on

San Dionisio, Parañaque City

Plate A-1

Figure 7. Liquefaction Analysis for BH-03 

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Subsurface Investigation for the Alkhemy Office Warehouse Lot 2, PCS-00-015243, Amvel Business Park, Brgy. San Dionisio, Parañaque City

Shallow Sha llow Foundation Based on the results of the subsurface investigation and considering the anticipated loads of the warehouse, utilization of shallow foundation system is feasible. Considering the variability of the subsoil, it is recommended that an integrated shallow foundation system consisting shall of spread tie beams or mat footing be used. Depth of foundation be atfootings least 2.0with meters from existing ground level, ensuring adequate footing embedment. Within the level of loose sand, an allowable soil bearing capacity of 60 kPa (~1,200 psf) may be adopted for analysis considering dead and codal live loads. The usual one-third overload factor for analysis considering transient loads may not be applied on this project site because of its liquefaction susceptibility In general, Terzaghi’s bearing capacity (general ( general shear failure) theory was used in the computation of the ultimate bearing capacity, the equation of which is given as qult 



qc



qq



q 



c' N    c



  1  D f  N q  

1 2

 2 BN  

  where q ult   = ultimate gross bearing capacity or soil bearing pressure c'

  = cohesion of the soil below foundation level

 1  = effective unit weight of soil above foundation level   2  = effective unit weight of soil below foundation level

f ooting below lowest lowest adjacent soil surface  D  f   = depth of footing  N c  N q  N    = soil-bearing capacity factors, dimensionless terms, whose ,

 

,

values relate to the angle of internal friction,   .  

'

 A factor of safety of 3.0 was adopted to obtain the safe bearing pressure. Deformation criteria (settlements) were considered in coming up with the allowable bearing capacity. Ground Improvement Depending on the structural load calculations, a higher bearing capacity may be required. As such, ground improvement techniques such as utilizing jet grouted piles, and stone columns may be adopted. These technologies aimed to improve the subsoil condition which will consequently increase the bearing capacity. It is important to note that it is essential to understand the system and limitations of each ground improvement technique before application.  Alternatively, reinforced concrete micro pile with typical diameters of 150mm to  Alternatively, 300 mm may also be utilized. The length of pile should at least be able to bypass the liquefiable liquefiable layers.

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Subsurface Investigation for the Alkhemy Office Warehouse Lot 2, PCS-00-015243, Amvel Business Park, Brgy. San Dionisio, Parañaque City

Excavations for Foundation Water level at the project area is known to be generally shallow. As such, provision for dewatering should be made (particularly during the rainy season) to ensure that excavations and subsequent construction of footings are undertaken under relatively dry condition. Moreover, stability of excavation cutswarranted. shall be ensured. Adequate shoring and bracingthe shall be provided, whenever Design De sign of Retainin Retainin g Structur es In the stability analysis and design of excavation supports or retaining walls, the following parameters may be used. This generally assumes the parameters of loose sand: Table 6: Geotechnical Parameters Parameters

 An gl e of fr ic ti on, on , Cohesion, Cohe sion, c Unit Weight,

28° Nil 17 kN/m3 

Lateral loads due to surcharge, as well as the dynamic thrust in the occurrence of an earthquake, shall also be considered in the analysis and design. Design of Pavements and Slabs-on-Grade It is recommended that the subgrade underneath pavements and slabs-ongrade be compacted to 95% MDD (maximum dry density). The provision of gravel bedding (crushed aggregates base course), 100 to 150 mm thick, is also recommended to provide a free-draining base course. Seismi Se ismi c Design Considerations If the seismic provisions of the NSCP (2015) shall be adopted, the proximity of near seismic sources shall be considered. The most prominent seismic source near the project site is the West W est Valley Fault. Based on the Fault Map published by PHIVOLCS, the trace of the West Valley Fault is located approximately 6.1 kilometers east of the project site. Considering the distance and characteristics of the West Valley Fault, the following seismic parameters are recommended: Table 7: Seismic Pa Parameters rameters

Seismi Se ismi c Source

West Valley Fault

Distance from the fault

~ 6.1 kilometers k ilometers

Soil Profile

SD 

Zone factor

0.4

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Subsurface Investigation for the Alkhemy Office Warehouse Lot 2, PCS-00-015243, Amvel Business Park, Brgy. San Dionisio, Parañaque City

Near Source Factors N a  and Nv, and Seismic Coefficient Ca  and Cv  shall be based on NSCP 2015 provisions as stated in Table 208-5 and 208-6, and Table 208-7 to 8, respectiv respectively. ely.

 

Project Area

Figure 8. Locatio n of t he Project Site wi th Respect to th e Ne Nearest arest Acti ve Fault (PH (PHIVO IVOLCS) LCS)

7.0

OTHER COMMENTS The foregoing findings and recommendations are generally based on the results of the subsurface investigation carried out by Soil-Philippines Index Testing, Inc. consisting of three (3) ( 3) boreholes. Should any difference in the site subsoil conditions be observed during construction, the undersigned must be informed so that further evaluation and necessary changes in the recommendations can be made. The design of pavements, foundation and substructures are beyond the scope of this report.

26 April 2017

JOHN MICHAEL B. GARGULLO  GARGULLO  Civil-Geotechnical Engineer   PRC No. 116709  116709 

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